GLUCOMYLASE PRODUCTION AND NITROGEN NUTRITION IN ASPERGILLUS-AWAMORI

Studies related to glucoamylase (GA) production and nitrogen nutrition have been reported, and there has been a general agreement as to its importance, although no conclusions have emerged. The present investigation studies the physiological response of an industrial strain of Aspergillus awamori to variable nitrogen nutrition and C/N ratios on GA production. It relates to the use of amino and NH4+ nitrogen or a combination of both. Conditions have been identified that favor the enzyme production. The negative effect of NH4+ concentrations on products, such as antibiotics, pullulan, ligninases, and proteases, is reported in the literature. In some cases, nitrogen metabolite repression has been considered to explain the data obtained. This work discusses a possible role played by nitrogen metabolite repression in glucoamylase production. Batch experiments were carried out in an 8-L working volume fermenter.